This article explores the extensive casualization of work and its impact on the working life of the people in South Korea after the financial crisis in 1997. A drastic increase in precarious workers was an immediate consequence of the neoliberal economic reform implemented by the new democratic government, including the enhancement of flexibility in the labor market and the restructuring of the financial market, under the guidance of the International Monetary Fund. Precarious work in South Korea has dramatically increased in the past decade, including both nonregular workers and precarious self-employment in the formal sector. Above all, proliferation of new types of nonregular employment in the 2000s has witnessed the significant transformation of the world of work in South Korea, deepening inequality and poverty. The extremely liberalized labor market tends to result in the fierce labor struggle of nonregular workers, not entitled to be members of unions, replacing the labor movement of regular workers’ labor unions.